Know that nothing which exists remains in a state of repose, that is to
say, all things are in motion. Everything is either growing or declining,
all things are either coming from non-existence into being, or going from
existence into non-existence. So this flower, this hyacinth, during a
certain period of time was coming from the world of non-existence into
being, and now it is going from being into non-existence. This state of
motion is said to be essential--that is, natural; it cannot be separated
from beings because it is their essential requirement, as it is the
essential requirement of fire to burn.
Thus it is established that this movement is necessary to existence, which
is either growing or declining. Now, as the spirit continues to exist
after death, it necessarily progresses or declines: and in the other
world, to cease to progress is the same as to decline; but it never leaves
its own condition, in which it continues to develop. For example, the
reality of the spirit of Peter, however far it may progress, will not
reach to the condition of the Reality of Christ; it progresses only in its
own environment.
Look at this mineral: however far it may evolve, it only evolves in its
own condition; you cannot bring the crystal to a state where it can attain
to sight: this is impossible. So the moon which is in the heavens, however
far it might evolve, could never become a luminous sun; but in its own
condition it has apogee and perigee. However far the disciples might
progress, they could never become Christ. It is true that coal could
become a diamond, but both are in the mineral condition and their
component elements are the same.